The fighting also killed three militants in the village of Bato-Bato in Indanan town, said Major Ramon David Hontiveros, a spokesman for the military’s Western Mindanao Command.

Hontiveros did not say how many soldiers died in the attack, but independent sources said at least 8 marines were killed when Abu Sayyaf militants opened fire on them. Nine other soldiers were injured in the ambush.

“We are getting conflicting reports as to the number of military casualties,” Hontiveros said.

The military earlier said fighting subsided in the province after Sunday clashes in Indanan killed an Abu Sayyaf militant and wounded four government soldiers.

Hontiveros said troops clashed with more than 200 militants in the town and that dozens had come from the nearby province of Basilan and reinforced the group of Abu Sayyaf leader Isnilon Hapilon.

It was unknown why the military failed to detect or intercept about 40 Abu Sayyaf gunmen who arrived by boat in Sulu on Sunday morning.

The fighting in the province erupted after security forces shelled suspected Abu Sayyaf and Jemaah Islamiya lairs in Indanan town, but a senior rebel leader of the Bangsamoro National Liberation Front, Madarang Sali, said the offensive targeted former Moro rebels under Khaid Ajibun.

Sali said the military attacked Ajibun’s camp without provocation, an accusation strongly denied by the military.

“We are not attacking the MNLF camp. The operation is directed at the Abu Sayyaf and Jemaah Islamiya position in the village of Buanza in Indanan town,” Hontiveros said.

Military and police intelligence reports said several Jemaah Islamiya terrorists are hiding and being by Abu Sayyaf militants in Sulu - among them are Mauiya, Dulmatin, Zulkifli bin Hir and Umar Patek - who are all wanted by Indonesia for the spate of deadly attacks in the Philippines and Indonesia, including the Bali bombing in 2002. The US has offered at least $16 million rewards for their capture.

The United States listed the Abu Sayyaf and the Jemaah Islamiya as foreign terrorist groups alongside with Osama bin Laden's al-Qaeda network.

Philippine authorities said the Jemaah Islamiya terrorists fled to Mindanao where they sought refuge under the protection of the Abu Sayyaf and rogue members of the Moro Islamic Liberation Front, the country’s largest Muslim rebel group. (With a report from Nickee Butlangan)